The negative influence of N-mediated TMV resistance on yield in tobacco: linkage drag versus pleiotropy
| Autor: | L. R. Linger, M. F. Wolff, E. A. Wernsman, Ramsey S. Lewis |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Germplasm
Genetic Linkage Biology Transformation Genetic Pleiotropy Genetic variation Tobacco Genetics Tobacco mosaic virus Inbreeding Nicotiana glutinosa Cultivar Transgenes Cloning Molecular Plant Diseases Plant Proteins fungi food and beverages General Medicine Plants Genetically Modified Immunity Innate Tobacco Mosaic Virus Horticulture Transformation (genetics) Mutagenesis Insertional Backcrossing Agronomy and Crop Science Biotechnology |
| Zdroj: | TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik. 115(2) |
| ISSN: | 0040-5752 |
| Popis: | Resistance to tobacco mosaic virus (TMV) is controlled by the single dominant gene N in Nicotiana glutinosa L. This gene has been transferred to cultivated tobacco (N. tabacum L.) by interspecific hybridization and backcrossing, but has historically been associated with reduced yields and/or quality in flue-cured tobacco breeding materials. Past researchers have suggested the role of pleiotropy and/or linkage drag effects in this unfavorable relationship. Introduction of the cloned N gene into a TMV-susceptible tobacco genotype (cultivar 'K326') via plant transformation permitted investigation of the relative importance of these possibilities. On average, yield and cash return ($ ha(-1)) of 14 transgenic NN lines of K326 were significantly higher relative to an isoline of K326 carrying N introduced via interspecific hybridization and backcrossing. The negative effects of tissue culture-induced genetic variation confounded comparisons with the TMV-susceptible cultivar, K326, however. Backcrossing the original transgenic lines to non-tissue cultured K326 removed many of these unfavorable effects, and significantly improved their performance for yield and cash return. Comparisons of the 14 corresponding transgenic NN backcross-derived lines with K326 indicated that linkage drag is the main factor contributing to reduced yields in TMV-resistant flue-cured tobacco germplasm. On average, these transgenic lines outyielded the conventionally-developed TMV-resistant K326 isoline by 427 kg ha(-1) (P < 0.05) and generated $1,365 ha(-1) more (P < 0.05). Although transgenic tobacco cultivars are currently not commercially acceptable, breeding strategies designed to reduce the amount of N. glutinosa chromatin linked to N may increase the likelihood of developing high-yielding TMV-resistant flue-cured tobacco cultivars. |
| Databáze: | OpenAIRE |
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